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authorMichael S. Tsirkin <mst@redhat.com>2013-03-17 02:46:09 +0000
committerDavid S. Miller <davem@davemloft.net>2013-03-17 14:28:54 -0400
commit46aa92d1ba162b4b3d6b7102440e459d4e4ee255 (patch)
tree98dd50e4b0420724c04fe00b188155fcb41a4476 /drivers/vhost
parent3d84fa98aca7f05f7010022bc45acb1b50326332 (diff)
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vhost/net: fix heads usage of ubuf_info
ubuf info allocator uses guest controlled head as an index, so a malicious guest could put the same head entry in the ring twice, and we will get two callbacks on the same value. To fix use upend_idx which is guaranteed to be unique. Reported-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Cc: stable@kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/net.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 959b1cd89e6a..ec6fb3fa59bb 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -339,7 +339,8 @@ static void handle_tx(struct vhost_net *net)
msg.msg_controllen = 0;
ubufs = NULL;
} else {
- struct ubuf_info *ubuf = &vq->ubuf_info[head];
+ struct ubuf_info *ubuf;
+ ubuf = vq->ubuf_info + vq->upend_idx;
vq->heads[vq->upend_idx].len =
VHOST_DMA_IN_PROGRESS;